To put it simple, the following are the NOT HAVE rules to be followed in the definition of a view;

1. Aggregate Functions2. Distinct, Group By, Having3. Sub Queries4. Reference to a non-updateable view in the FROM clause5. Sub Query6. Temporary Tables7. No duplicate view column Names8. All columns in the base table not having Default Value should be included in the View Definition9. Columns should be simple and not derived Reference / Further Reading: